Added changes-5.3.1 file.

General comment about documentation fixes

Change-Id: Ie344dd701da02ab9c344b5ffd39e4d0c9b6ea31f
Reviewed-by: Sergio Ahumada <sahumada@blackberry.com>
Reviewed-by: Topi Reiniö <topi.reinio@digia.com>
Merge remote-tracking branch 'origin/5.3.1' into 5.3

Change-Id: Ib12a908dce5ea0286c90937fe282c11b495d3927
Merge "Merge remote-tracking branch 'origin/5.3.1' into 5.3" into refs/staging/5.3